轮缘封严气流与主流干涉的损失机理研究

Investigation on Interaction Loss Mechanism Between Rim Seal Flow and Mainstream

关键词:  涡轮  转静盘腔  封严气流  干涉  损失机理

Key words:  Turbine  Stator-rotor cavity  Rim seal flow  Interaction  Loss mechanism

摘要:

为了研究涡轮转静盘腔中轮缘封严气流与主流干涉的损失机理，开展了在有无封严气流工况下轮缘封严气流与主流干涉的损失机制和分解量化方法研究。结果表明，轮缘封严气流与主流干涉存在四种损失机制：粘性剪切损失、堵塞效应损失、二次流交互作用损失以及第二级静子的附加损失。设计工况下粘性剪切损失的比例为67.68%，而其它三种损失的比例相当。随着封严流量增大，封严出流的流量和径向速度不断增大而周向速度不断减小，造成四种损失都不断增大。相对于设计工况，每1%封严流量使得总损失平均增大约为104.25%。所建立的损失量化体系准确地捕捉到了转子堵塞效应损失和二次流交互作用损失不断增大的分布，证明损失量化体系是可行和有效的。

Abstract:

In order to investigate the interaction loss mechanisms between turbine stator-rotor cavity rim seal flow and mainstream, investigations were conducted on the loss factors and isolation method for interaction between the rim seal flow and mainstream for the case with and without the rim seal flow. The results show that four loss factors are considered, namely viscous shear loss, blockage effect loss, secondary flow interaction loss and second stator additional loss. Among these four loss factors, the percent of viscous shear loss is 67.68% at design condition. In addition, the percent of other three loss factors approaches each other. With the increment of rim seal flow rate, the mass flow rate and radial velocity of egress flow increase and the circumferential velocity of egress flow reduces, which leads four losses to increase. Relative to the design condition, the total loss increases by approximately 104.25% per 1% increase in the rim seal flow rate. Furthermore, the established loss quantitative system exactly captures the increasing trend of blockage effect loss in rotor domain and secondary flow interaction loss. Therefore, the loss quantitative system is further proven to be feasible and effective.